Short answer: the Partybox Ultimate if you want the deepest bass available and always have it near an outlet; the Bromley 750 if you need it to actually run on battery. These rank #11 and #1 out of 11 large-party speakers, at $1299.99 and $1499.95, with the Partybox Ultimate costing $199.96 more.
The Partybox Ultimate has no battery at all - it’s mains-power only. That’s the real dividing line between these two, more than sound quality: the Bromley 750 runs 40-plus hours cordless, while the Ultimate has to stay plugged in. In exchange, the Ultimate is rated at 1100W against the Bromley 750’s 400W, and our own notes call it the absolute deepest bass of any Bluetooth speaker we’ve covered - a category the Bromley 750 doesn’t compete in, given its own notes flag its bass as not particularly deep and its frequency response as unremarkable.
Both are wheeled and heavy - the Ultimate is the bigger of the two at 39 kg (86 lbs) against the Bromley 750’s 23.9 kg (52.7 lbs) - and both take guitar and karaoke-style microphone input, with the Bromley 750 adding true XLR-level jacks the Ultimate doesn’t have.
Buy the Partybox Ultimate if raw bass depth is the priority and portability isn’t. Buy the Bromley 750 if you actually need it to run away from an outlet.
If sound quality matters at all to you, skip the Marshall Bromley 750. It ranks near the bottom of the 11 large party speakers, so look higher up the list instead.
Specifications Side By Side
| Marshall Bromley 750 | JBL Partybox Ultimate | |
|---|---|---|
| Price | $1299.99 | $1,499.95 |
| Ranked | #11 of 11 in Large Party Size Portable Bluetooth Speakers | #1 of 11 in Large Party Size Portable Bluetooth Speakers |
| Aux Input | Yes (3.5mm, RCA) | Yes |
| Battery Life | 40+ hours (Manufacturer specified) | No Battery |
| Bluetooth Codecs | SBC, AAC, LC3 | SBC |
| Guitar Input | Yes | Yes |
| IP Rating | IP54 | IPX4 |
| Microphone Input | Yes (2x XLR/6.35mm combo) | Yes (Karaoke mode with echo effect) |
| Power Bank | Yes (USB-C) | Yes (USB-A, 5V/2.1A) |
| Power Input | USB-C | AC Power cord |
| Weight | 52.7 lbs / 23.9 kg | 86 lbs / 39 kg |
| XLR Input | Yes (2x combo) | - |
| App | Yes (Marshall Bluetooth app) | Yes |
| Built in Microphone | No | No |
| EQ | Yes | Yes (3 band) |
| Party Mode | Yes (Auracast) | Yes (Auracast) |
| Stereo | Yes | Yes |
| TWS | No | Yes |
| USB Playback | No | Yes |
| Wifi | No | Yes |
| Bluetooth Version | 5.3 | 5.3 |
| Dimensions | 16.3" x 25.7" x 14" (413 x 652 x 355 mm) | 17.9" x 41.3" x 17.3" (455 x 1049 x 440 mm) |
| Drivers | 2x 10" woofers, 2x 5.25" mid-ranges, 2x 1" tweeters, 2x 0.8" tweeters | 2x 9" subwoofer, 2x 4.5" midrange, 2x 2.75" tweeter |
| Output Power | 400W | 1100W |
| Digital Aux Input | Yes (USB-C) | No |
| Removable Battery | Yes | - |
| Charging Time | 3.5 hours | - |
| Frequency Response | 20Hz - 20kHz (Manufacturer specified) | - |
| Discontinued | No | - |
The Two Speakers In Full
Marshall Bromley 750: $1299.99 Amazon
Pros: Much wider, more consistent off-axis dispersion than the JBL Partybox 720, which only fires forward - the Marshall’s standout feature, sounding about the same from any angle.
Cons: Not as deep bass as the JBL Partybox 330 or JBL Partybox 720. Not a great frequency response overall, with some midrange peaks. Only basic bass/treble controls, no full custom EQ like the JBL Partybox 720’s app. Default bass (dynamic mode) is overdone out of the box and needs trimming.
Full Marshall Bromley 750 review and specifications →
| App | Yes (Marshall Bluetooth app) |
|---|---|
| Aux Input | Yes (3.5mm, RCA) |
| Battery Life | 40+ hours (Manufacturer specified) |
| Bluetooth Codecs | SBC, AAC, LC3 |
| Bluetooth Version | 5.3 |
| Built in Microphone | No |
| Charging Time | 3.5 hours |
| Digital Aux Input | Yes (USB-C) |
| Dimensions | 16.3" x 25.7" x 14" (413 x 652 x 355 mm) |
| Discontinued | No |
| Drivers | 2x 10" woofers, 2x 5.25" mid-ranges, 2x 1" tweeters, 2x 0.8" tweeters |
| EQ | Yes |
| Frequency Response | 20Hz - 20kHz (Manufacturer specified) |
| Guitar Input | Yes |
| IP Rating | IP54 |
| Microphone Input | Yes (2x XLR/6.35mm combo) |
| Output Power | 400W |
| Party Mode | Yes (Auracast) |
| Power Bank | Yes (USB-C) |
| Power Input | USB-C |
| Removable Battery | Yes |
| Stereo | Yes |
| TWS | No |
| USB Playback | No |
| Weight | 52.7 lbs / 23.9 kg |
| Wifi | No |
| XLR Input | Yes (2x combo) |
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- Links
- Reviews, Comparisons and Sound Samples
- Joy & Oluv’Sone: Marshall Bromley 750 vs JBL Partybox 720 - outdoor test
- Storytripper HD: W-King T12 vs Marshall Bromley 750
- Danny Pops: I Finally Got The Marshall Bromley 750 Everyone Wanted
- Oluv Patreon: JBL Partybox 720 vs Marshall Bromley 750
- Oluv Patreon: Marshall Bromley 750 - battery issues in the cold
- Oluv Patreon: Marshall Bromley 750 & Teufel Rockster Air 2 - outdoor test
- Oluv Patreon: Marshall Bromley 750 - 2nd look after update
- Oluv Patreon: Marshall Bromley 750 - first impressions
- Reddit Search for Marshall Bromley 750 Review
- Head-to-Head Comparisons
JBL Partybox Ultimate: $1,499.95 Amazon Bhphotovideo
Pros: Absolute deepest bass of any Bluetooth speaker. Handle and wheels are convenient. Very nice lightshow ability.
Cons: Very large and heavy. No battery. Note, JBL daisychain is not compatible with any other non-JBL speaker and is possibly a fully digital signal.
Full JBL Partybox Ultimate review and specifications →
| App | Yes |
|---|---|
| Aux Input | Yes |
| Battery Life | No Battery |
| Bluetooth Codecs | SBC |
| Bluetooth Version | 5.3 |
| Built in Microphone | No |
| Digital Aux Input | No |
| Dimensions | 17.9" x 41.3" x 17.3" (455 x 1049 x 440 mm) |
| Drivers | 2x 9" subwoofer, 2x 4.5" midrange, 2x 2.75" tweeter |
| EQ | Yes (3 band) |
| Guitar Input | Yes |
| IP Rating | IPX4 |
| Microphone Input | Yes (Karaoke mode with echo effect) |
| Output Power | 1100W |
| Party Mode | Yes (Auracast) |
| Power Bank | Yes (USB-A, 5V/2.1A) |
| Power Input | AC Power cord |
| Stereo | Yes |
| TWS | Yes |
| USB Playback | Yes |
| Weight | 86 lbs / 39 kg |
| Wifi | Yes |
As an eBay Partner, we may be compensated if you make a purchase.
- Links
- Reviews, Comparisons and Sound Samples
- GYMCADDY: JBL Partybox Ultimate Vs SOUNDBOKS 4 & Sony XV900 - Is It Worth It?
- GYMCADDY: JBL Partybox Ultimate Vs Partybox 710 - They’re Both Crazy, But There Is A Clear Winner
- Flossy Carter: JBL PartyBox Ultimate VS JBL PartyBox 1000 - Which Speaker is The BEST?
- GYMCADDY: JBL Partybox 720 Vs JBL Partybox Ultimate
- GYMCADDY: Sony ULT Tower 10 Vs JBL Partybox Ultimate & JBL Partybox 710
- Reddit Search for JBL Partybox Ultimate Review
- Head-to-Head Comparisons
- JBL Partybox Ultimate vs JBL Partybox 1000
- JBL Partybox Ultimate vs JBL Partybox 720
- JBL Partybox Ultimate vs JBL Partybox 710
- JBL Partybox Ultimate vs JBL Partybox 520
- JBL Partybox Ultimate vs Sony ULT Tower 9
- JBL Partybox Ultimate vs Sony ULT Tower 10
- JBL Partybox Ultimate vs Soundboks 4
- JBL Partybox Ultimate vs W-King T12
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Product prices and availability were last checked August 12, 2026 at 5:33 PM UTC and are subject to change; the price and availability shown on Amazon at the time of purchase will apply to the purchase of this product.